气相色谱法测定食品中丙酸及其盐类

目的]建立固体及液态食品中丙酸含量测定的气相色谱方法.方法]用水蒸气蒸馏法将食品中存在的丙酸及其盐类共沸蒸馏,以丁酸做内标,采用HP-FFAP柱（30 m×0.32 mm×0.25μmn）对其进行分离.以保留时间定性,试样中丙酸和正丁酸峰面积比与标准系列比较定量.结果]试验表明,丙酸在1.0 ～50.0 mg范围内线性关系良好,相关系数R2 =0.999 8,面条与酱油中丙酸的添加回收率分别为94.8％～ 97.3％和99.5％～102.6％,变异系数分别为0.62％ ～1.49％和0.63％ ～ 0.93％,定量限为0.025 g/kg.结论]该方法简便、快速、可靠,可用于市售食品中丙酸含量的测定.

Determination of Propionic Acid and its Salts in Food by Gas Chromatography

Objective] A method was developed to determine the concentration of propionic acid and its salts in solid and liquid food by GC.Method] Propionic acid was extracted from foods by steam distillation.By using butyric acid as internal standard,the separation of propionic acid was achieved on HP-FFAP column （30 m × 0.32 mm × 0.25 μm） with gradient temperature program.Qualitative analysis was conducted by the retention times and quantitation by internal standard.Result] The standard curve of propionic acid was linear （R2 =0.999 8） and the concentration range was from 1.0 mg to 50 mg.The average recovery rate of propionic acid in fresh noodles was from 94.8％ to 97.3％ and RSD was from 0.62％ to 1.49％.And the average recovery rate of propionic acid in soy sauce was from 99.5％ to 102.6％ and RSD was from 0.63％ to 0.93％.The limit of quantitation was 0.025 g/kg.Conclusion] This method is simple,rapid,reliable and suitable for measuring total content of propionic acid in food.